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2005 | 108 | 2 | 395-401
Article title

EPR Study of Ammonium Nitrate Doped with Copper(II) Ions

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Abstracts
EN
This work is devoted to a study of the structural changes in a single crystal of ammonium nitrate, NH_4NO_3, doped with copper(II) cations by electron paramagnetic resonance. Ammonium nitrate crystallizes at atmospheric pressure in several polymorphic forms, phase VII → V → IV → III → II → I → melt, with transition temperatures of 103 K, 255 K, 305 K, 357 K, 398 K, and 443 K, respectively. The aim of our work was to study the temperature phase transition V → IV at about 255 K using electron paramagnetic resonance technique. The electron paramagnetic resonance spectra were performed using an X-band spectrometer with microwave frequency of 9.4 GHz and magnetic modulation of 100 kHz in the temperature range of 153-296 K. For a single crystal the angular dependence of the copper(II) electron paramagnetic resonance spectra was measured at 293 K and 168 K. The anisotropic behaviour measured at 293 K points to the existence of one kind of two equivalent copper(II) complexes with inverse g and A tensors. A second pair of equivalent complexes also with inverse g and A tensors was observed. The minimal values of g-factors correspond to the maximum values of A. The angular dependence taken at 168 K shows the existence of two types of non-equivalent copper complexes which differ in comparison with the complexes observed at room temperature. The temperature dependence of the intensities of hyperfine structure lines for all copper(II) complexes observed shows a phase transition V → IV occurring in the temperature range of 237-246 K with a hysteresis. One of the hyperfine structure lines of a copper(II) complex measured at low temperatures shows a superhyperfine structure with line intensities 1:2:3:2:1 originating from the interaction of the copper ^{63,65}Cu (I=3/2) nucleus with two ^{14}N (I = 1) nuclei of two ammonia, NH_3, ligand molecules.
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Contributors
author
  • Institute of Physics, University of Zielona Góra, Prof. Z. Szafrana 4a, 65-516 Zielona Góra, Poland
  • Institute of Physics, University of Zielona Góra, Prof. Z. Szafrana 4a, 65-516 Zielona Góra, Poland
References
  • 1. C.S. Choi, J.E. Mapes, E. Prince, Acta Crystallogr. B, 28, 1357, 1972
  • 2. M. Ahtee, K.J. Smolander, B.W. Lucas, A.W. Hewat, Acta Cryst. C, 39, 651, 1983
  • 3. W. Wojtowicz, A.B. Wickowski, in: XX International Seminar on Radio- and Microwave Spectroscopy RAMIS'03 in Inhomogeneous Systems, April, Poznań 2003, Abstracts, P-14
  • 4. F.J. Owens, J. Appl. Phys., 53, 368, 1982
  • 5. U. Tumkurkar, A. Anand, H.L. Bhat, S.V. Bhat, in: Modern Applications of EPR/ESR: From Biophysics to Materials Science, Proceedings of the First Asia-Pacific EPR/ESR Symposium, January, Hong Kong 1997, Eds. Cz.Z. Rudowicz, K.N. Yu, H. Hiraoka, Springer-Verlag, Singapore 1998, p. 453
  • 6. S.K. Hoffmann, Acta Phys. Pol. A, 49, 253, 1976
  • 7. C.S. Choi, H.J. Prask, E. Prince, J. Appl. Cryst., 13, 403, 1980
  • 8. Ya.Ya. Abolin'sh, S.V. Karpov, A.A. Shultin, Sov. Phys., Solid State, 20, 3660, 1978
  • 9. E. Di Mauro, W. Sano, J. Phys., Condens. Matter, 6, L81, 1994
Document Type
Publication order reference
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bwmeta1.element.bwnjournal-article-appv108n222kz
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